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[Qemu-devel] [RFC 0/4] virtio-mmio transport
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [RFC 0/4] virtio-mmio transport |
Date: |
Mon, 14 Nov 2011 14:55:24 +0000 |
This set of patches implements the QEMU end of the MMIO virtio transport
(as specified by Appendix X of the latest virtio spec from here
http://ozlabs.org/~rusty/virtio-spec/virtio.pdf
and implemented by patches which I think are going into Linux 3.2).
I submit this only as an RFC because although it works (tested
virtio-blk anyway) it has some issues:
* extra vring alignment field not saved/restored (because virtio
layer isn't using VMState and doesn't allow the virtio base layer
to specify a version for its data so back-compat would be tricky)
* you have to specify which kind of virtio device you want in the
board model. In particular this means that for virtio-blk the user
has to say "-drive if=none,file=whatever.img,id=myimg
-global virtio-blk-mmio.drive=myimg" or the virtio-blk layer will
refuse to start, which is not at all userfriendly
Anthony's suggestion was that we should have a qdev bus between
the transport layer and the -blk/-net/-etc parts. Then the board could
instantiate N virtio-mmio transport instances, and the user uses
-device to create a virtio-blk device and assign it to the relevant
slot. (PCI virtio would also split similarly so you'd end up with
pci-controller -> n lots of [ virtio-pci-transport + virtio-blk])
plus some syntactic sugar for back-compatibility I guess.)
However I'm not currently sure when I'll have time to do that
refactoring, so I'm just sending this patchset out as an RFC
for now.
Peter Maydell (4):
virtio: Add support for guest setting of queue size
virtio: Support transports which can specify the vring alignment
Add MMIO based virtio transport
hw/vexpress.c: Add MMIO virtio transport
Makefile.objs | 1 +
hw/vexpress.c | 3 +
hw/virtio-mmio.c | 426 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
hw/virtio.c | 20 +++-
hw/virtio.h | 2 +
5 files changed, 450 insertions(+), 2 deletions(-)
create mode 100644 hw/virtio-mmio.c
- [Qemu-devel] [RFC 0/4] virtio-mmio transport,
Peter Maydell <=
- [Qemu-devel] [RFC 2/4] virtio: Support transports which can specify the vring alignment, Peter Maydell, 2011/11/14
- [Qemu-devel] [RFC 3/4] Add MMIO based virtio transport, Peter Maydell, 2011/11/14
- [Qemu-devel] [RFC 4/4] hw/vexpress.c: Add MMIO virtio transport, Peter Maydell, 2011/11/14
- [Qemu-devel] [RFC 1/4] virtio: Add support for guest setting of queue size, Peter Maydell, 2011/11/14
- Re: [Qemu-devel] [RFC 0/4] virtio-mmio transport, Stefan Hajnoczi, 2011/11/14
- Re: [Qemu-devel] [RFC 0/4] virtio-mmio transport, Paolo Bonzini, 2011/11/16